The present invention relates to the synthesis of L-phenylalanine and analogues thereof and more particularly to a process wherein L-phenylalanine ammonia-lyase enzyme is desensitized to elevated concentrations of trans-cinnamate, ring substituted trans-cinnamates and various acrylate derivtives.
The synthesis of L-phenylalanine from trans-cinnamate and ammonia or an ammonia donor using L-phenylalanine ammonia-lyase enzyme has been disclosed in several publications and patents. However, these prior attempts to effect this reaction have been, as a practical matter, unsuitable for commercial scale processing. The reaction between trans-cinnamate and ammonia to produce L-phenylalanine is thermodynamically unfavorable. The reported equilibrium constant value of 4.7 M necessitates the use of ammonia concentrations greater than 4.7 M to achieve a trans-cinnamate to L-phenylalanine conversion of more than fifty percent. Moreover, L-phenylalanine ammonia-lyase is inhibited by cinnamate even at low cinnamate concentration. Phenylalanine ammonia-lyase activity at 250 mM cinnamate concentration has been reported to be only about one percent of the activity at a concentration of 50 mM. Hence, processes disclosed heretofore require a dilute cinnamate concentration which unavoidably increases product recovery cost.
It is the overall object of the present invention to provide a process having increased productivity.
Accordingly, it is an object of the present invention to provide a process having an increased rate of reaction.
It is another object of the present invention to provide a process capable of operating at much higher cinnamate concentrations than processes disclosed heretofore.
It is yet another object of the present invention to provide a process wherein L-phenylalanine ammonia-lyase enzyme is desensitized to elevated concentrations of trans-cinnamate, ring substituted trans-cinnamates and various acrylate derivatives.
These and other objects, features, and advantages of the present invention will be evident to one skilled in the art from the following description.